Heart disease is the leading cause of morbidity and mortality in the Western World. As this is mostly[unreadable] related to disorders of the blood supply to the heart, it is very important to be able to assess the perfusion of[unreadable] the heart wall. Conventional methods for assessing myocardial perfusion have many limitations, including[unreadable] relatively low resolution and poor ability to provide quantitative data. Magnetic resonance imaging (MRI) of[unreadable] the "first-pass" kinetics of contrast enhancement by a bolus injection of contrast agent is a very promising[unreadable] method for noninvasive assessment of myocardial perfusion, with higher resolution than conventional[unreadable] radionuclide imaging methods. However, current approaches to MRI perfusion studies have only been "semiquantitative",[unreadable] due to several technical difficulties.[unreadable] We have been achieving very encouraging initial results in making absolute measurements of regional[unreadable] myocardial perfusion, using novel MRI methods that we have designed to overcome the limitations of[unreadable] conventional MRI approaches. In the proposed research, we will further develop our MRI methods, and the[unreadable] associated image analysis methods, for quantitatively measuring myocardial perfusion. We will perform a[unreadable] series of studies on normal subjects to establish the expected range of variability of the results. We will also[unreadable] perform a series of studies of patients with coronary artery disease, comparing the results of our MRI[unreadable] methods with those of conventional methods used to assess the blood supply to the heart, including[unreadable] radionuclide imaging, CT angiography and conventional cardiac catheterization (including invasive measures[unreadable] of flow reserve).[unreadable] The significance of the proposed work is its potential to achieve more accurate and higher resolution[unreadable] assessments of blood flow to the heart wall than current conventional methods can provide. This would be[unreadable] very useful for aiding treatment decisions and for following the results of therapy in patients with ischemic[unreadable] heart disease, a common and serious clinical condition. The quantitative MRI methods we propose to[unreadable] develop for the assessment of cardiac vascular disease may also be applicable to assessment of the[unreadable] perfusion of other important organs, such as the brain, which is subject to stroke, and in other important[unreadable] disease processes, such as cancer, where the disease evolution may be related to blood flow.